1. Field of the Invention
The present invention relates to an operating device, particularly for vehicles, such as, for example, airplanes or buses, and particularly relates to an operating device comprising a board, such as a printed circuit board carrying the electronics, the board being fastened by, for example, of a special catch connection.
2. Description of the Background Art
Almost all means of transport are equipped with key buttons as operating devices for drive functions or service functions. Typically, these key buttons were composed of a front panel integrated into the interior covering panels and a switching portion located behind it and being operable by means of the front panel, which is typically arranged directly on a printed circuit board so that the switching information can be directly transmitted to a monitor or evaluation circuit.
A problem with this arrangement is that the printed circuit board has to take up the force applied upon actuation of the key button. This requires a special fastening of the printed circuit board. For the purposes of exchange and repair, the fastening of the printed circuit board should be releasable.
To this end, front panels with catch hooks exist that first bend apart upon insertion of the printed circuit board and move back again when the printed circuit board has reached a final position, so that the printed circuit board is locked into place. Typically, these catch hooks are arranged at the border of the printed circuit board and receive the latter between them. Operating devices comprising a printed circuit board held by such catch hooks are known from DE-C-100 01 053, DE-U-83 28 123, EP-A-0 841 673 and U.S. Pat. No. 4,750,091. Further, an operating element is known from EP-A-0 984 673 the housing of which consists of interlocked parts.
Each catch hook of known operating devices consists of a flexible base part permitting the bending-apart and a contact portion arranged at the end of the base part, for retaining the printed circuit board. The contact portion engages over the border of the printed circuit board and is supported there to secure the printed circuit board against pressure. If now, upon the actuation of an operating element (e.g., key button) located on the printed circuit board, pressure is exerted upon it, a force arises that is directed away from the front face of the operating device. Up from a certain force acting upon the printed circuit board, caused by actuating a key button, for example, the connection between the printed circuit board and the conventional catch hook is undone by the corresponding torque, since the catch hooks bend outward so far until they no longer engage the printed circuit board. Then, the printed circuit board is no longer secured and is displaced out of its position by a further induction of force, which leads to an undesired failure of the key buttons.
It is, therefore, an object of the present invention to provide an operating device for a vehicle with an improved fastening of the board.
In order to solve this object, the invention suggests an operating device for vehicles, being provided with a board, and at least two encompassing elements receiving the board between them, each of which comprises a contact portion retaining the board and a base part supporting the contact portion.
In this operating device, it is provided, according to the invention, that at least one of the encompassing elements is configured as an elastic catch hook and that the contact portion of the at least one catch hook is arranged on that side of its base part that faces away from the respective other encompassing element, wherein, upon the exertion of force upon the board in the direction of the contact portion of the at least one catch hook, the latter can be subjected to a torque towards the respective other encompassing element.
The invention suggests an operating device in which at least one encompassing element is configured as an elastically bendable catch hook the base part of which faces the opposed encompassing element and the contact portion of which faces away from the opposed encompassing element. When the board is loaded in the direction of the normal line of the board and onto the contact portions of the encompassing element or catch hook, a torque is exerted onto the at least one catch hook in the direction of the encompassing element. This results in that the catch hook is pressed even more strongly onto the board when loaded. This, in turn, results in that the board cannot be released from between the catch hook and the other encompassing element that has, in this case, a substantially rigid configuration, even in case of a very great force.
Preferably, an acute angle (i.e. an angle smaller than 90xc2x0) is formed between the contact portion and the base part so that the contact portion is supported on the board with an edge and not with a surface. This facilitates the movement of the contact portion over the board when the latter is locked into place and increases the torque in case of loads acting upon the board.
Preferably, recesses are provided at the border of the board in which the catch hook and/or the encompassing member are arranged. This arrangement provides for a particularly stable fixing of the board.
Advantageously, the contact portion of the catch hook rises above the recesses in the board at two opposed recess borders so that the base part of the catch hook is able to move in the recess whereas the contact portion is supported on the board and holds the latter. As an alternative or in addition thereto, the contact portion rises above the border of the recess connecting the two afore-mentioned borders.
The board can be configured as a printed circuit board with or for electric and/or electronic circuits or components.
Preferably, the one encompassing element, which is not formed as a catch hook is rigid. This encompassing element can also extend over the entire lateral edge of the board or a part thereof.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.